The present invention relates to the detection of a nucleic acid hybrid by chemiluminescent reactions. It is known that chemiluminescent detection is one of the most sensitive ways of detecting an analyte. The process, although sensitive, suffers from several disadvantages. In most cases the chemiluminescent reaction mediated emission of light has a very short lifetime, i.e., light emission is very quick, so that a sophisticated device has to be developed to monitor the extent of light emission and also to determine the extent of the presence of an analyte. It is also difficult to couple the interacting systems to the analyte without destroying or changing the property of the interacting partners.
Recently, it has been demonstrated that if a substance, for example, an iodophenol or a benzothiazole derivative is present during the chemiluminescent emission mediated by horseradish peroxidase, the reaction rate is retarded and simultaneously the quantum yield of the light emission is enhanced (European Patent Application No. 0 116 454; European Patent Application No. 0 103 784; UK Patent Application No. 820 62 63; Gary H. G. Thorpe, Robert Haggart, Larry J. Kricka and Thomas P. Whitehead, "Enhanced Luminescent Enzyme Immunoassays For Rubella Antibody, Immunoglobulin And Digoxin", Biochemical and Biophysical Research Communications, Vol. 119, No. 2, pp. 481-487, March 15, 1984; Thomas P. Whitehead, Gary H. G. Thorpe, Timothy J. N. Carter, Carol Groucutt and Larry J. Kricka, "Enhanced Luminescence Procedure For Sensitive Determination Of Peroxidase-labelled Conjugates In Immunoassay", Nature, Vol. 305, pp. 158-159, Sept. 8, 1933; Gary H. G. Thorpe, Larry J. Kricka, Eileen Gillespie, Susan Mosely, Robert Amess, Neil Baggett and Thomas P. Whitehead, "Enhancement Of The Horseradish Peroxidase Catalysed Chemiluminescent Oxidation Of Cyclic Diacyl Hydrazides By 6-Hydroxybenzothiazoles", Anal. Biochem.). Although this method has been shown to be useful in the detection of an analyte by conventional immunoassay methods, it has never been demonstrated, however, whether this method could be utilized to detect a nucleic acid hybrid.
It has been demonstrated heretofore that a chemiluminescent reaction occurs where the emission is due to an iron initiated activation of bleomycin. The self-inactivation reaction is affected by the presence of DNA.
In Photochemistry Photobiology, Vol. 40, pg 823-830, (1984), it was described that photoemission is quenched by target molecules such as DNA and that the presence of DNA does not prevent the iron-initiated activation of bleomycin, by the so-called self-inactivation reaction associated with chemiluminescence. The article went on to state that these findings seem to suggest that an electronically excited intermediate of bleomycin can alter bio-molecules though, in that case, the nature of the excited state was not precise. Swedish patent application No. 8200479 describes chemiluminescent detection of nucleic acid hybrids. European patent application No. 0 070 687 concerns a light-emitting polynucleotide hybridization diagnostic method.